An additive manufacturing multi-unit powder spreading device and a powder spreading method thereof

Abstract

The present invention discloses a novel multi-pack powder spreading device for additive manufacturing and a powder spreading method thereof. The novel multi-pack powder spreading device includes a printer outer frame, a laser, a forward and backward moving screw, an upward and downward moving screw, a toner cartridge fixing frame, a conveyor belt pulley fixing frame, a powder spreading detection laser, a substrate, a positioning detector, a printer laser module, a conveyor belt, a conveyor belt pulley, two or more sets of electrostatic powder spreading devices, and a controller. Each set of electrostatic powder spreading devices includes a powder suction roller, a charging roller, a toner cartridge, a transfer roller, an irradiation laser, a toner cartridge box fixing frame, and a toner cartridge. The novel multi-pack powder spreading device can also increase the lifespan of parts when working in high-temperature environments. The novel multi-pack powder spreading device can be used to spread a mesh structure of powder of a high thermal conductivity material inside the part to accelerate the heat dissipation of the part and increase the lifespan of the part. The present invention also has the advantages of being able to achieve the goal of not requiring re-washing when changing powder during the printing process, saving the manufacturing cost of the parts, and having high control precision.

Description

Technical Field

[0001] The present invention relates to the technical field of metal additive manufacturing, and in particular to a multi-unit powder spreading device and a powder spreading method for additive manufacturing. Background Art

[0002] Since the 20th century, traditional metal manufacturing technologies have been unable to meet the growing demands of specialized industries such as aerospace technology, automotive manufacturing, and medical equipment. Against this backdrop, a series of advanced metal additive manufacturing technologies, represented by selective laser melting, are experiencing rapid development. Metal additive manufacturing is a novel forming process that utilizes modeling software such as CAD / CAM, ProE, and UG to create a three-dimensional model, then gradually adds materials based on this model. This process can also be simply understood as rapid prototyping, digital manufacturing, layered manufacturing, or solid-state free-form manufacturing. The entire process boasts a short cycle time, high-precision molded parts, and the ability to recycle excess powder. It has been hailed as the "industrial revolution manufacturing technology" of our time.

[0003] Selective laser melting is considered an advanced additive manufacturing technology of the new era and has recently been successfully used in the manufacture of various metal materials, especially high-performance parts with complex structures. This technology not only enables the production of finished components with high dimensional accuracy, perfect surface quality, and excellent performance, but also enables a low-cost, high-efficiency manufacturing process to meet the requirements of high-precision, high-strength structural parts in industries such as aerospace, defense, automotive, and medical devices. Compared with traditional metal additive manufacturing methods (such as direct energy deposition and electron beam melting), selective laser melting technology has the following advantages: high forming accuracy and low surface roughness, high laser energy can melt powder materials more quickly, saving time and cost, and powder materials can be recycled repeatedly, making it a green and environmentally friendly manufacturing method.

[0004] Because selective laser melting (SLM) technology only allows for a single type of metal powder to be used during the powder coating phase, changing the powder mid-process requires re-purging, which is time-consuming and labor-intensive. Since only one type of metal powder can be used to cover the entire substrate at a time, it is impossible to create specialized structures with different metal powders to enhance part performance. When manufacturing parts using SLM, each powder coating must cover the entire substrate, requiring several times, or even dozens or even hundreds of times, more metal powder than the part itself. Furthermore, the remaining metal powder must be sieved after each print, making post-print cleanup extremely time-consuming and labor-intensive. Furthermore, in order to enhance the tensile or compressive properties of parts manufactured using SLM, rare earth elements are often added to the material, requiring extensive testing and time-consuming experiments. Changing the powder mid-production requires opening the sealed hatch and waiting for a long time for re-purging, wasting inert gas resources and time. Summary of the Invention

[0005] The first purpose of the present invention is to provide a multi-unit powder-laying device for additive manufacturing. The present invention lays out metal powder of a specific shape in the powder-laying stage. When laying a single layer of powder on a part, the first powder-laying device can lay out the main powder of the part (there is no powder at the skeleton or heat dissipation network position in the single layer of powder on the part), and then use the second powder-laying device to fill the unpowdered areas inside the part with tensile or compressive metal powder, in the hope that a tensile or compressive metal skeleton will be formed inside the part when the production is completed, so as to improve the tensile or compressive performance of the part.

[0006] The second object of the present invention is to provide a multi-pack powder laying method for additive manufacturing.

[0007] The first object of the present invention is achieved in this way:

[0008] A new multi-unit powder spreading device for additive manufacturing, comprising a fully enclosed printer outer frame and a controller, characterized in that: the printer laser module is fixed in the middle of the top inside the printer outer frame, the front and rear moving screw rods are fixed on the left and right sides of the bottom inside the printer outer frame, the substrate is fixed in the middle of the bottom inside the printer outer frame, the part to be printed is fixed on the substrate, the positioning detector is fixed between the left side of the bottom inside the printer outer frame, the substrate and the left front and rear moving screw rod, on the left and right sides inside the printer outer frame and above the front and rear moving screw rods, there is a vertical moving screw rod respectively, the bottom end of each vertical moving screw rod is vertically connected to the front and rear moving screw rod through a screw nut; on the side of the vertical moving screw rods on the left and right sides, there is a conveyor belt wheel respectively, the two conveyor belt wheels are in the same horizontal direction, each conveyor belt wheel is connected to the middle of the adjacent vertical moving screw rod through a horizontally placed conveyor belt wheel fixing frame, the conveyor belt is wound around the two conveyor belt wheels and tightened, and metal part sliced powder is fixed at the bottom of the conveyor belt, and the metal part sliced powder faces the part to be printed below; the bottom ends of the left and right side plates of the "冂"-shaped drum fixing frame outer frame are respectively fixed on the left and right side conveyor belt wheel fixing frames, and the powder spreading detection laser is fixed on the inner wall of the left side plate of the drum fixing frame outer frame; between the top plate of the drum fixing frame outer frame and the conveyor belt, there are more than two sets of electrostatic powder spreading devices, each set of electrostatic powder spreading device includes a powder suction roller, a charging roller, a drum, a transfer roller, an irradiation laser, a drum cartridge fixing frame and a drum cartridge, the drum cartridge is fixed on the top plate inside the drum fixing frame outer frame through the drum cartridge fixing frame, the irradiation laser is fixed on the left side of the top plate inside the drum cartridge, the charging roller, the drum, the transfer roller and the powder suction roller with a metal powder box are all connected through the brackets inside the drum cartridge, the powder suction roller and the charging roller are respectively located above the left and right of the drum and are tangent to the drum, the transfer roller is located directly below the drum, the conveyor belt is sandwiched between the drum and the transfer roller, the drum contacts the upper surface of the conveyor belt, and the transfer roller contacts the lower surface of the conveyor belt; the printer laser module is provided on the top plate inside the printer outer frame; the powder suction roller, the charging roller, the drum, the transfer roller, the front and rear moving screw rods, the vertical moving screw rods, and the conveyor belt wheels are respectively connected to the controller through their respective drive motors, and the irradiation laser, the powder spreading detection laser, the positioning detector, and the printer laser module are respectively connected to the controller through wires.

[0009] The height of the powder spreading detection laser is slightly higher than the height of the conveyor belt and is directly opposite to the bottom of the drum.

[0010] The second object of the present invention is achieved as follows:

[0011] A new multi-unit powder spreading method for additive manufacturing, characterized in that: the specific steps are as follows:

[0012] A. Under the control of the controller, first use the first electrostatic powder spreading device to spread powder, charge the drum with the charging roller of the first electrostatic powder spreading device, so that the drum is negatively charged;

[0013] B. Irradiation laser: Use laser to scan the toner cartridge, so that the non-parts pattern area of the toner cartridge is discharged except for the parts pattern. The part pattern area of the toner cartridge is not irradiated by the laser and therefore does not discharge, but carries static electricity.

[0014] C. The powder suction roller rotates to absorb the metal powder in the metal powder box and contacts the toner cartridge, transferring the metal powder to the toner cartridge;

[0015] D. The toner drum, transfer roller and conveyor belt rotate synchronously, and the transfer roller has an opposite and greater charge than the toner drum, so that the metal powder is transferred to the conveyor belt;

[0016] E. Move the screw back and forth to align the bottom center of the conveyor belt with the part. Then the conveyor belt rotates to move the metal powder to the bottom of the conveyor belt. Then the positioning detector detects the positioning point on the conveyor belt to ensure that the metal powder is aligned with the part. The conveyor belt stops rotating.

[0017] F. Move the screw forward and backward to move the metal powder to the top of the part, then move the screw up and down to move the conveyor belt downward so that the metal powder on the conveyor belt contacts the part;

[0018] G. After contact, the parts are electrified. The charge of the parts is opposite to that of the metal powder on the conveyor belt, and the charge number is larger. At this time, due to the electrostatic attraction between opposite charges, the metal powder on the conveyor belt will be transferred and adsorbed on the surface of the parts.

[0019] H. The outer frame of the toner cartridge fixing frame, the conveyor belt, the first electrostatic powder spreading device, and the second electrostatic powder spreading device are driven by the up and down moving screw rod to move upward first, and then the screw rod moves forward and backward to make the entire powder spreading structure leave working space for the printer laser module;

[0020] I. The printer laser module starts working, melting the metal powder on the part, completing the first layer of metal part printing and preparing to print the next layer;

[0021] J. Use the second electrostatic powder spreading device to spread powder and repeat steps A-G to complete the second layer of part printing;

[0022] The pattern of the metal skeleton in the finished product is a cross, a tic-tac-toe, a grid, a circle, a rectangle, a triangle or an irregular shape.

[0023] The multi-unit powder spreading device of the present invention includes a fully enclosed printer frame, a laser, a forward and backward moving screw, a vertical moving screw, a toner cartridge mounting frame, a conveyor pulley mounting frame, a powder spreading detection laser, a substrate, a positioning detector, a printer laser module, a conveyor belt, a conveyor pulley, two or more electrostatic powder spreading devices, and a controller. Each electrostatic powder spreading device includes a powder suction roller, a charging roller, a toner cartridge, a transfer roller, an irradiation laser, a toner cartridge mounting frame, and a toner cartridge. The novel multi-unit powder spreading device can be used to enhance the performance of a part by using metal additive manufacturing technology to create a metal skeleton with a tensile or compressive metal inside the part. For example, if the main structure of the part is aluminum alloy, a tensile metal material can be used to create the skeleton to enhance the tensile properties of the aluminum alloy. Alternatively, in a cylindrical aluminum alloy pressure-bearing part, the novel multi-unit powder spreading device can be used to add dozens or hundreds of metal needles made of high-compression metal powder along the direction of force during the powder spreading stage using zone laser melting technology to improve the performance of the part. For example, a tensile metal skeleton can be created inside a bolt to impart high tensile properties.

[0024] The metal skeleton can be of various shapes.

[0025] Therefore, the present invention has the following advantages:

[0026] 1. In the powder laying stage, a skeleton shape is formed by using metal powder with tensile or compressive properties on the main powder pattern of the part (not mixed). After multiple printings, the high-strength metal powder can form a tensile or compressive metal skeleton inside the part to improve the tensile or compressive mechanical properties of the part;

[0027] 2. Avoid opening and closing the sealed hatch when changing powder in the middle of printing parts, avoid gas waste caused by re-washing, and save the manufacturing cost of parts;

[0028] 3. A laser detection device has been added to detect the conveyor belt after the powder is laid to check the quality of the powder;

[0029] 4: Simple transmission, reasonable structure and high control precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 Figure 1 A top view of

[0032] FIG3 is a schematic diagram of the structure of metal powder laid out by the first electrostatic powder laying device;

[0033] FIG4 is a schematic diagram of the metal powder structure laid out by the second electrostatic powder laying device;

[0034] FIG5 is a schematic diagram of the structure of metal powder after passing through the first electrostatic powder spreading device and the second electrostatic powder spreading device;

[0035] Figure 6 is a schematic diagram of the structure of a metal part produced using the present invention, Figure a represents a schematic diagram of the structure of a part produced by the present invention, Figure b represents a schematic diagram of a part using a cross-shaped skeleton, and Figure c represents a schematic diagram of a part using a well-shaped skeleton. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings. Example 1

[0037] A novel multi - unit powder spreading device for additive manufacturing, comprising a fully enclosed printer outer frame 18 and a controller. The printer laser module 15 is fixed at the middle of the top inside the printer outer frame 18. The front - and - rear moving screw rod 6 is fixed on the left and right sides of the bottom inside the printer outer frame 18. The substrate 13 is fixed at the middle of the bottom inside the printer outer frame 18. The part 10 to be printed is fixed on the substrate 13. The positioning detector 14 is fixed between the left side of the bottom inside the printer outer frame 18, the substrate 13 and the left - hand front - and - rear moving screw rod 6. On the left and right sides inside the printer outer frame 18, above the front - and - rear moving screw rod 6, there is a vertical moving screw rod 7 respectively. The bottom end of each vertical moving screw rod 7 is perpendicularly connected to the front - and - rear moving screw rod 6 through a screw nut. On the side of each of the vertical moving screw rods 7 on the left and right sides, there is a conveyor belt wheel 21. The two conveyor belt wheels 21 are in the same horizontal direction. Each conveyor belt wheel 21 is connected to the middle of the adjacent vertical moving screw rod 7 through a horizontally placed conveyor belt wheel fixing bracket 9. The conveyor belt 17 is wound around the two conveyor belt wheels 21 and is tightened. The metal part sliced powder 16 is fixed at the bottom of the conveyor belt 17, and the metal part sliced powder 16 faces the part 10 to be printed below. The bottom ends of the left and right side plates of the "冂" - shaped drum fixing frame outer frame 8 are respectively fixed on the left and right conveyor belt wheel fixing brackets 9. The powder spreading detection laser 11 is fixed on the inner wall of the left side plate of the drum fixing frame outer frame 8. Between the top plate of the drum fixing frame outer frame 8 and the conveyor belt 17, there are two identical first electrostatic powder spreading devices 22 and second electrostatic powder spreading devices 23 arranged side by side. The first electrostatic powder spreading device 22 is on the left, and the second electrostatic powder spreading device 23 is on the right. The first electrostatic powder spreading device 22 and the second electrostatic powder spreading device 23 both include a powder suction roller 1, a charging roller 2, a drum 3, a transfer roller 4, an irradiation laser 5, a drum cartridge fixing bracket 19 and a drum cartridge 20. The drum cartridge 20 is fixed on the top plate inside the drum fixing frame outer frame 8 through the drum cartridge fixing bracket 19. The irradiation laser 5 is fixed on the left of the top plate inside the drum cartridge 20. The charging roller 2, the drum 3, the transfer roller 4 and the powder suction roller 1 with the metal powder box 12 are all connected through the brackets inside the drum cartridge 20. The powder suction roller 1 and the charging roller 2 are respectively located above the left and right of the drum 3 and are tangent to the outer surface of the drum 3. The transfer roller 4 is located directly below the drum 3. The conveyor belt 17 is sandwiched between the drum 3 and the transfer roller 4. The drum 3 contacts the upper surface of the conveyor belt 17, and the transfer roller 4 contacts the lower surface of the conveyor belt 17. The printer laser module 15 is provided on the top plate inside the printer outer frame 18. The powder suction roller 1, the charging roller 2, the drum 3, the transfer roller 4, the front - and - rear moving screw rod 6, the vertical moving screw rod 7, the conveyor belt wheel 21 are respectively connected to the controller through their respective drive motors. The irradiation laser 5, the powder spreading detection laser 11, the positioning detector 14, the printer laser module 15 are respectively connected to the controller through wires.

[0038] The height of the powder spreading detection laser 11 is slightly higher than the height of the conveyor belt 17 and is directly opposite to the bottom of the drum 3.

[0039] A new multi-pack powder laying method for additive manufacturing, the specific steps are as follows:

[0040] A. First, metal powder is added to metal powder 12. Under the control of the controller, the first electrostatic powder spreading device 22 is used to spread the powder. First, the charging roller 2 of the first electrostatic powder spreading device 22 charges the toner drum 3, so that the toner drum 3 is negatively charged.

[0041] B. Irradiating laser 5 scans the toner drum 3 with laser light, so that the non-part pattern area of the toner drum 3 except the pattern of the part 10 is discharged, and only the area where the toner drum 3 transfers the pattern of the slice of the part 10 is charged;

[0042] C. The powder suction roller 1 rotates to absorb the metal powder in the metal powder box 12 and contacts the toner drum 3, transporting the metal powder and adsorbing it to the charged area of the toner drum 3;

[0043] D. The toner drum 3, transfer roller 4 and conveyor belt 17 rotate synchronously, and the transfer roller 4 carries a larger charge opposite to that of the toner drum 3, so that the metal powder 16 is transferred to the conveyor belt 17;

[0044] E. Move the screw rod 6 back and forth to align the bottom center of the conveyor belt 17 with the part 10. The conveyor belt 17 then rotates to move the metal powder to just above the part 10. The positioning detector 14 then detects the positioning point on the conveyor belt 17 to ensure that the metal powder 16 is aligned with the part 10. The conveyor belt 17 then stops rotating.

[0045] F. Move the screw 6 back and forth to rotate the metal powder to be directly above the part 10, then move the screw 7 up and down to rotate the conveyor belt 17 downward so that the metal powder on the conveyor belt 17 contacts the part 10;

[0046] G. After contact, the part 10 is electrified. The charge of the part 10 is opposite to the charge of the metal powder 16 on the conveyor belt 17 and the charge is greater. At this time, due to electrostatic attraction, the metal powder 16 on the conveyor belt 17 will be transferred and adsorbed on the surface of the part 10.

[0047] H, the outer frame of the toner cartridge holder 8, the conveyor belt 17, the first electrostatic powder spreading device 22, the second electrostatic powder spreading device 23, the entire powder spreading structure first moves upward under the drive of the up and down moving screw 7, and then the screw 6 moves back and forth to make the entire powder spreading structure, leaving working space for the printer laser module 15;

[0048] I. The printer laser module 15 starts working, melting the metal powder 16 on the part 10, completing the printing of the first layer of the metal part and starting to prepare for printing the next layer;

[0049] J. Use the second electrostatic powder spreading device 23 to spread powder and repeat steps A-G to complete the second layer of part printing;

[0050] K. Use different metals to lay out metal skeletons with different structures in the single layer powder of part 10 to obtain the finished product.

[0051] The use of a new multi-mounted powder laying device can realize the use of metal additive manufacturing technology to use a tensile or compressive metal to make a metal skeleton inside the part to enhance the performance of the part. For example, if the main structure of the part is aluminum alloy, a tensile metal material is used as the skeleton to enhance the tensile properties of the aluminum alloy. Or in cylindrical aluminum alloy pressure-bearing parts, regional laser melting technology is used to use a new multi-mounted powder laying device to add dozens or hundreds of metal needles made of high-compressive metal powder along the force direction during the powder laying stage to improve the performance of the part.

[0052] The metal skeleton in Example 1 is Figure 5 The cross in the. Example 2

[0053] The structure of Example 2 is the same as that of Example 1, except that:

[0054] Example 2 prints three layers, uses the first electrostatic powder spreading device 22 to spread powder again, repeats steps A-G, completes the third layer of metal part printing, and uses different metals to spread different structures in the single layer of powder of the part to obtain a finished product.

[0055] The metal skeleton in Example 2 is Figure 6 The tic-tac-toe shape in the picture.

Claims

1. A novel multi-pack powder spreading device for additive manufacturing, comprising a fully enclosed printer frame and a controller, characterized by: The printer laser module is fixed at the middle of the top inside the printer outer frame. The front and rear moving screw rods are fixed on the left and right sides of the bottom inside the printer outer frame. The substrate is fixed at the middle of the bottom inside the printer outer frame. The part to be printed is fixed on the substrate. The positioning detector is fixed between the left side of the bottom inside the printer outer frame, the substrate and the front and rear moving screw rod on the left side. On the left and right sides inside the printer outer frame, above the front and rear moving screw rods, there is a vertical moving screw rod each. The bottom end of each vertical moving screw rod is vertically connected to the front and rear moving screw rod through a screw nut. On the side of the vertical moving screw rods on the left and right sides, there is a conveyor belt wheel each. The two conveyor belt wheels are in the same horizontal direction. Each conveyor belt wheel is connected to the middle of the adjacent vertical moving screw rod through a horizontally placed conveyor belt wheel fixing bracket. The conveyor belt is wound around the two conveyor belt wheels and tightened. There is a metal part sliced powder fixed at the bottom of the conveyor belt, and the metal part sliced powder faces the part to be printed below. The bottom ends of the left and right side plates of the "冂"-shaped drum fixing frame outer frame are respectively fixed on the left and right side conveyor belt wheel fixing brackets. The powder spreading detection laser is fixed on the inner wall of the left side plate of the drum fixing frame outer frame. Between the top plate of the drum fixing frame outer frame and the conveyor belt, there are more than two sets of electrostatic powder spreading devices. Each set of electrostatic powder spreading device includes a powder suction roller, a charging roller, a drum, a transfer roller, an irradiation laser, a drum cartridge fixing frame and a drum cartridge. The drum cartridge is fixed on the top plate inside the drum fixing frame outer frame through the drum cartridge fixing frame. The irradiation laser is fixed on the left side of the top plate inside the drum cartridge. The charging roller, the drum, the transfer roller and the powder suction roller with a metal powder box are all connected through the brackets inside the drum cartridge. The powder suction roller and the charging roller are respectively located above the left and right of the drum and are tangent to the drum. The transfer roller is located directly below the drum. The conveyor belt is sandwiched between the drum and the transfer roller. The drum contacts the upper surface of the conveyor belt, and the transfer roller contacts the lower surface of the conveyor belt. The printer laser module is fixed on the top plate inside the printer outer frame. The powder suction roller, the charging roller, the drum, the transfer roller, the front and rear moving screw rods, the vertical moving screw rods, the conveyor belt wheels are respectively connected to the controller through their respective drive motors. The irradiation laser, the powder spreading detection laser, the positioning detector, the printer laser module are respectively connected to the controller through wires.

2. The novel multi-unit powder spreading device for additive manufacturing according to claim 1 is characterized in that: The height of the powder spreading detection laser is slightly higher than the height of the conveyor belt and is directly facing the bottom of the drum.

3. A novel multi-pack powder spreading method for additive manufacturing, characterized by: The specific steps are as follows: A. Under the control of the controller, first use the first electrostatic powder spreading device to spread powder. Charge the drum with the charging roller of the first electrostatic powder spreading device to make the drum negatively charged. B. The irradiation laser scans the drum with laser, so that the non-part pattern area of the drum except the part pattern area discharges. The part pattern area of the drum is not irradiated by laser and does not discharge, so it is electrostatic. C. The powder suction roller rotates to adsorb the metal powder in the metal powder box and contacts the drum to transfer the metal powder to the drum. D. The drum, the transfer roller and the conveyor belt rotate synchronously, and the transfer roller has a charge opposite to and greater than that of the drum, so that the metal powder is transferred to the conveyor belt. E. Move the screw back and forth to align the bottom center of the conveyor belt with the part. Then the conveyor belt rotates to move the metal powder to the bottom of the conveyor belt. Then the positioning detector detects the positioning point on the conveyor belt to ensure that the metal powder is aligned with the part. The conveyor belt stops rotating. F. Move the screw forward and backward to move the metal powder to the top of the part, then move the screw up and down to move the conveyor belt downward so that the metal powder on the conveyor belt contacts the part; G. After contact, the parts are electrified. The charge of the parts is opposite to that of the metal powder on the conveyor belt, and the charge number is larger. At this time, due to the electrostatic attraction between opposite charges, the metal powder on the conveyor belt will be transferred and adsorbed on the surface of the parts. H. The outer frame of the toner cartridge fixing frame, the conveyor belt, the first electrostatic powder spreading device, and the second electrostatic powder spreading device are driven by the up and down moving screw rod to move upward first, and then the screw rod moves forward and backward to make the entire powder spreading structure leave working space for the printer laser module; I. The printer laser module starts working, melting the metal powder on the part, completing the first layer of metal part printing and preparing to print the next layer; J. Use the second electrostatic powder spreading device to spread powder and repeat steps A-G to complete the second layer of part printing; K. Use different metals to lay out metal skeletons with different structures in the single layer of powder of the part to obtain the finished product.

4. The novel multi-pack powder spreading method for additive manufacturing according to claim 3, characterized in that: The pattern of the metal skeleton in the finished product is a cross, a tic-tac-toe, a grid, a circle, a rectangle, a triangle or an irregular shape.

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